Optical mark recognition is the process of capturing data by contrasting reflectivity at predetermined positions on a page. By shining a beam of light onto the document the scanner is able to detect a marked area because it reflects less light than an unmarked surface. Some OMR devices use forms which are preprinted onto ‘Transoptic’ paper and measure the amount of light which passes through the paper, thus a mark on either side of the paper will reduce the amount of light passing through the paper.
Optical mark recognition is generally distinguished from optical character recognition by the fact that a recognition engine is not required. That is, the marks are constructed in such a way that there is little chance of not reading the marks correctly. This does require the image to have high contrast and an easily-recognizable or irrelevant shape. One of the most familiar applications of optical mark recognition is the use of #2 or HB pencil bubble optical answer sheets In multiple choice examinations. Students mark their answers, or other information, by darkening circles marked on a pre-printed sheet. Afterwards the sheet is automatically graded by a scanning machine. In most European countries, a horizontal or vertical ‘tick’ in a rectangular ‘lozenge’ is the most commonly used type of OMR form, the most familiar application being the UK National lottery form. Lozenge marks are a later technology and have the advantage of being easier to mark and easier to erase. The large ‘bubble’ marks are legacy technology from the very early OMR machines that were so insensitive a large mark was required for reliability. In most Asian countries, a special marker is used to fill in an optical answer sheet. Students, likewise mark answers or other information via darkening circles marked on a pre-printed sheet. Then the sheet is automatically graded by a scanning machine.
On of the most prevalent optical mark recognition systems in use is the traditional Scantron test scoring system. The Scantron system is usually seen as a multiple-choice, fill-in-the-bubble form of varying length and width, ranging from single-column, 15-answer tests, to forms of several 8.5×11 inch pages used in standardized testing, such as the SAT and the ACT. The forms are read optically, using optical mark recognition to detect markings in each place, in a “Scantron Machine”, which tabulates results. Earlier versions were sensed electrically.
Commonly, there are two sides to Scantron answer sheets. They can contain 50 answer blanks, 100 answer blanks, and so on. A smaller form, called a “Quiz Strip”, provides answer space for only about 20 questions. On the back of larger sheets is a space in which answers to other kinds of questions can be written. The 8.5×11-inch form may contain a larger area for working math problems, write long-hand answers, etc. Answers “A” and “B” are commonly used for “True or False” questions.
It is common for Scantron sheets to have instructions such as “Do not make any stray marks on the answer sheet”, “Fill in each circle/square completely. To change your answer completely erase the mark” and “Please use a Number 2 pencil”.
Grading of Scantron sheets is performed first by creating an answer key. The answer key is simply a standard Scantron answer sheet with all of the correct answers filled in, along with the “key” rectangle at the top of the sheet. The key is fed into the Scantron machine, which stores the correct answers in the memory. Further sheets fed are graded according to the key in memory. Switching the machine off stops the paper feed and clears the memory. Incorrect answers are marked with a red dash, or the correct answer (unless the correct answer is made up of multiple letters, such as BCE, in which case it will be marked with an asterisk), down the left side of the paper. In this way, students see which questions they answered correctly. The number of correct answers is printed on the form. It can also show a percentage grade along with the number of answers correct.
Although tests administered using optical mark recognition systems such as Scantron are relatively secure, they are not immune to attempts at cheating. One method often used is for one student to attempt to determine a pattern in the answer sheet of an adjacent student. Thus, even though the individual answer numbers may be too far away to be read, the position of answers in the answer columns may still be discernible. Unless an exam proctor catches the student in the act, this type of cheating is difficult to detect and thwart. Students have been known to copy patterns of answers from various neighboring students, making it particularly difficult to prove that they have cheated. Peer pressure is sometimes exerted on knowledgeable students to make their answer sheets easier to copy, for example, by making excessively dark marks on the response form.
In several contexts of varying relevance to test taking, the privacy of response forms has been the subject of inventive effort, and is reflected in the patent literature. For example, U.S. Pat. No. 5,154,616 to Hegardt is directed to an apparatus for obstructing a standardized test form from view of all but the test taker. The apparatus permits a test taker to see the necessary portions of the answer sheet but obstructs and obscures the view of answer marks from shallow angles or from a distance.
U.S. Pat. No. 4,971,560 to Patel shows a teaching aid for increasing the memorization of a large number of equations comprising a front cover having a vertical column of horizontally disposed completed equations visible thereon and which front cover forms a cut out portion adjacent the vertical column and a writing sheet which is removable and positionable under the cut out portion of said front cover for providing a replaceable writing area accessible through said cut out portion.
U.S. Pat. No. 4,852,268 to Sutherland describes a template intended for use with user marked lottery tickets. The template consists of two sheets of stiff material joined along a fold line. The sheets conform in shape and size to the lottery ticket to be marked. One sheet of the template is provided with an array of perforations outlining removable areas on the template that correspond in number, position and form to the user markable spaces on the lottery ticket. The template is preferably a transparent plastic material. In use, the removable areas corresponding to numbers to be marked on the lottery ticket are removed from the template so that a writing implement may be introduced through the resulting open areas for marking the desired spaces on the ticket. The template may be used not only for marking a ticket but for protecting the ticket from damage so that it can be used from time to time.
U.S. Pat. No. 3,995,381 to Manfred deals with a low visibility answer sheet and method of testing utilizing the same in which the answer areas on a multiple choice answer sheet are predarkened. The answers are made by darkening over a desired predarkened area. The contrast between a predarkened area which has been marked and a predarkened area which has not been marked by an examinee is significantly reduced and thus the potential for cheating by examinees viewing the answers entered by other examinees is decreased.
U.S. Pat. No. 1,781,047 to Bondeson discloses an educational device including an envelope having a plurality of openings and carrying test problems adjacent thereto. The answers to the problems are to be written by a student through the openings on a sheet of paper enclosed in the envelope. A sheet of cardboard is disposed in the envelope and back of the sheet of paper to afford an adequate writing surface for the paper, and to facilitate its placement in or removal from the envelope.
Although the arrangements described in these patents provide certain advantages, they present certain deficiencies as well. For example, many known devices require expensive and unwieldy optical filtering devices. Further, many of these devices are simply impractical for application in an academic testing environment. “Predarkened” answer sheets can present visibility problems for the examinee, resulting in entry errors, and may cause the examinee to make darker, easily-copied answer marks. Predarkening is also limited in its effectiveness when viewed at an angle. It can thus be seen that the need exists for a simple, efficient, and easily manufactured response form security system.